Suppose that X1 and X2 are independent random variables each with a mean μ and a variance σ^2. Compute the mean and variance of Y = 3X1 + X2.

Answers

Answer 1

Mean:

E[Y] = E[3X₁ + X₂]

E[Y] = 3 E[X₁] + E[X₂]

E[Y] = 3µ + µ

E[Y] = 4µ

Variance:

Var[Y] = Var[3X₁ + X₂]

Var[Y] = 3² Var[X₁] + 2 Covar[X₁, X₂] + 1² Var[X₂]

(the covariance is 0 since X₁ and X₂ are independent)

Var[Y] = 9 Var[X₁] + Var[X₂]

Var[Y] = 9σ² + σ²

Var[Y] = 10σ²


Related Questions

If the function f is given by f(x)= 4x -3, find the value of f(2+h)

Answers

f(x)=4x-3

[tex]\\ \sf\longmapsto f(2+h)[/tex]

[tex]\\ \sf\longmapsto 4(2+h)-3[/tex]

[tex]\\ \sf\longmapsto 4h+8-3[/tex]

[tex]\\ \sf\longmapsto 4h+5[/tex]


There is a sequence of rigid transformations that takes A to A', B to B', and C to "
same sequence takes D to D'. Draw and label D':

Answers

Answer:

I think it's D

Step-by-step explanation:

Answer:  I think its D

Step-by-step explanation:

Rigid transformation moves a shape without changing the size of the shape.

See attachment for the diagram that shows the position of D'

Someone please helppp

Answers

Answer:

k = 5/6

Step-by-step explanation:

First, we can make this have the form of a quadratic function, or ax²+bx+c=0. To do this, we can first subtract 10x from both sides to get

(2k+1)x²-8x=-6

Next, we can add 6 to both sides, resulting in

(2k+1)x²-8x+6 = 0

For a quadratic function of form ax²+bx+c=0, we can see that a=2k+1, b=-8, and c=6. We can then apply the quadratic equation, or

x= (-b ± √(b²-4ac))/(2a) to get our roots to be

x= (8 ± √(64-4(6)(2k+1)))/(2*(2k+1))

=  (8 ± √(64-(48k+24)))/(4k+2)

=  (8 ± √(40-48k))/(4k+2)

For the roots to be equal, we must have the two roots equal to each other. We can write this as

(8 + √(40-48k))/(4k+2) = (8 - √(40-48k))/(4k+2)

multiply both sides by (4k+2) to remove the denominator

8+√(40-48k) = 8 - √(40-48k)

subtract 8 from both sides to isolate the square roots

√(40-48k) = - √(40-48k)

The only number that is equal to its negative self (and is real) is 0. Therefore, √(40-48k) = - √(40-48k) = 0, so we have

√(40-48k) = 0

square both sides to remove the square root

40-48k = 0

add 48k to both sides to isolate the k and its coefficient

40 = 48k

divide both sides by 48 to isolate k

k = 40/48 = 5/6

What is the perimeter, rounded to the nearest tenth?
The area of the regular hexagon is 169.74 ft2.

A regular hexagon has an apothem with length 7 feet and an area of 169.74 feet squared.

What is the perimeter, rounded to the nearest tenth?

24.2 ft
28.3 ft
48.5 ft
56.8 ft

Answers

Answer: C. 48.5

Explanation:

When asked to find the perimeter of any regular hexagon given the area and apothem, you may apply the formula
a = 1/2 x a1 x p, where a is the area, a1 is the apothem, and p is of course the perimeter.

1) 169.74 = 1/2 x 7 x p
2) 169.74 x 2 = 7 x p
3) 339.48/7 = p
4) p = 48.497
5) ≈ 48.5

Hope this helps, brainliest would be appreciated :)

Answer:

48.5 ft

Step-by-step explanation:

Find the point on y axis which is equidistant from the point (5,-2) and (-3,2)

Answers

Answer:

(0, -2)

Step-by-step explanation:

a point on the y-axis. that means x=0.

so, the distance of (5, -2) to (0, y) is the same as the distance from (-3, 2) to (0, y).

the distance between (5, -2) and (0, y) is based on Pythagoras (the differences in x and y directions are the sides of a right-angled triangle, and the distance is its Hypotenuse, its baseline) :

distance² = (5-0)² + (-2 - y)² = 25 + 4 + 4y + y² = 29+4y+y²

but it is also

distance² = (-3-0)² + (2 - y)² = 9 + 4 - 4y + y² = 13 - 4y + y²

so, we get

29 + 4y + y² = 13 - 4y + y²

29 + 4y = 13 - 4y

16 = -8y

y = -16/8 = -2

their, the point on the y-axis being equidistant to both points is (0, -2)

Solve the following.
2x^2-7x-4/6x^2+7x+2<0
Can someone explain how to solve this.

Answers

Answer:

Which one have same variable gather or decrease up

Step-by-step explanation:

2x^2-4.6x^2=1.4x^2

-7x+7x=0

1.4x^2+2<0

x<0

For the function f(x)=x+9/7-4x find f^-1(x)

Answers

Answer:

Step-by-step explanation:

[tex]f(x)=\frac{x+9}{7-4x} \\put ~f(x)=y\\flip~x~and~y\\f(y)=x\\y=f^{-1}(x)\\y=\frac{x+9}{7-4x} \\flip~x~and~y\\x=\frac{y+9}{7-4y} \\x(7-4y)=y+9\\7x-4xy=y+9\\-4xy-y=9-7x\\or\\4xy+y=7x-9\\y(4x+1)=7x-9\\y=\frac{7x-9}{4x+1} \\or~f^{-1}(x)=\frac{7x-9}{4x+1}[/tex]

A trapezoid has two basses that measure 11 cm and 8 cm. The height of the figure is 5 cm. What is the area of the trapezoid? A) 95 cm2. B) 64 cm2. C) 47.5 cm2. D) 24 cm2

Answers

Answer:

C.47,5cm²

Step-by-step explanation:

The option which is not a solution of the equation 2x + 3y = 6 is:
(A) (0, 2)
(B) (1, 1)
(C) (-3, 4)
(D) (3, 0).​

Answers

Answer:

Step-by-step explanation:

B OR TRUE

Look at photo I tested each thing, your answer to this question in option B

A car travels 25 m/s for 30 seconds. What distance did the car travel ?

Answers

Answer:

750 meters

Step-by-step explanation:

Answer:

750m

Step-by-step explanation:

Distance= Speed x Time

Speed = 25m/s

Time = 30s

Distance = 25 x 30

              = 750 m

               

find 25th and 49th term of the sequence 50 ,46,42,38......​

Answers

Answer: -46

Step-by-step explanation:

[tex]u_1=50=50-(1-1)*4\\u_2=46=50-(2-1)*4\\u_3=42=50-(3-1)*4\\...\\\\u_n=50-(n-1)*4\\\\\\u_{25}=50-(25-1)*4=-46\\\\\\Answer\ -46\\[/tex]

Find the volume of each figure. Round your answers to the nearest tenth, if necessary​

Answers

Answer:

600

Step-by-step explanation:

Volume=l*b*h=5*12*10=600

A company determines that its weekly online​ sales, Upper S (t )​, in hundreds of​ dollars, t weeks after online sales began can be estimated by the equation below. Find the average weekly sales for the first 3 weeks after online sales began. Upper S (t )equals2 e Superscript t

Answers

Answer:

$1272.36 ( average weekly sales for first 3 weeks )

Step-by-step explanation:

weekly online sales = S(t)

Determine average weekly sales for first 3 weeks

S(t) = 2e^t

total sales = ∫ S(t) dt        

∴ Average weekly sales for first 3 weeks  ( note : S(t) = 2e^t  )

=  [tex]\int\limits^3_0 {2e^t \, dt / ( 3 - 0 )[/tex]            

= 2 [ e^t ] ³₀ / 3 = 2 ( e^3 - e^0 ) / 3 =  2 ( 6.3618 ) = 12.7236 hundreds

= $1272.36 ( average weekly sales for first 3 weeks )

Help anyone can help me do this question,I will mark brainlest.​

Answers

Answer:

18. 28 cm*2

19. 24 m

Step-by-step explanation:

18. length × l = 16

l*2= 16

l = 4

RQ = 4 cm

PR =7cm

Area of parallelogram = b×h

= 7×4

=28cm*2

19. 8 +8 + (6-2) +( 6- 2)

=24 m

Is {3,…} a defined set

Answers

Answer:

no it's not a defined state it's undefined

Find the value of x

HELPP PLEASEE
GIVING 20 points!!!

Answers

Answer:

A 6.09

Step-by-step explanation:

Answer if you want tho...

Answers

3 loaves and 3 bananas left over

Answer:

3 loaves 2 bananas left.

Step-by-step explanation:

The answer is asking how many loaves of three bananas Seth can make. 11 can be divided by 3 a total of 3 times, leaving a remainder of 2 bananas that would not be enough to make another loaf.

Two tangents drawn to a circle from a point outside it, are equal in length.prove it.

Answers

Given: A circle with centre O; PA and PB are two tangents to the circle drawn from an external point P.
To prove: PA = PB
Construction: Join OA, OB, and OP.
It is known that a tangent at any point of a circle is perpendicular to the radius through the point of contact.
OA⊥PA
OB⊥PB
In △OPA and △OPB
∠OPA=∠OPB (Using (1))
OA=OB (Radii of the same circle)
OP=OP (Common side)
Therefor △OPA≅△OPB (RHS congruency criterion)
PA=PB
(Corresponding parts of congruent triangles are equal)
Thus, it is proved that the lengths of the two tangents drawn from an external point to a circle are equal.
The length of tangents drawn from any external point are equal.
So statement is correct

Can someone help me with this

Answers

Answer:

Step-by-step explanation:

The standard form for a circle is

[tex](x-h)^2+(y-k)^2=r^2[/tex] and what's important here is that the x- and the y- remain that way in the equation. Filling in our values,

[tex](x-(6))^2+(y-(-3))^2=25[/tex] which tells us that our center is

        6      and     -3 -------------------> (6, -3)

The radius is the square root of 25 which is 5.

Please help me with this problem.

Answers

Answer:

Step-by-step explanation:

Remark

The cos(60) = 1/2

The radii marked 6 is the adjacent side. You have to solve for the hypotenuse.

Why?

Because the hypotenuse is the distance from the center of the circle to the point of intersection of the angle. Once you have the hypotenuse, you can find the length of the tangent, which will lead to the area of the kite. Then take away 1/3 the area of the circle.

Hypotenuse

Cos(60) = 1/2

cos(60) = adjacent / hypotenuse        Multiply both sides by the hypotenuse

hypotenuse * cos(60) = adjacent       Divide by Cos(60)

hypotenuse = adjacent / cos(60)  

adjacent = 6

hypotenuse = 6/0.5

hypotenuse = 12

Tangent

tangent^2 = 12^2 - 6^2

tangent^2 = 144 - 36

tangent^2 = 108

tangent = sqrt(108)

tangent = 6sqrt(3)

Triangles

The area of the triangle = 1/2 6sqrt(3) * 6

The area of the triangle = 18 sqrt(3)

There are two triangles so the area = 36 sqrt(3) That's the area of the kite.

Circle sector.

Area of the circle sector = 1/3 * pi * r^2

r = 6

Leave pi as it is.

Area of the circle sector = 1/3 * pi * 6^2

area of the circle sector = 12 pi

Answer

Area of the red part = area of the triangles - the area of circle sector

Area of the red part = 36*sqrt(3) - 12* pi            

Which expression is equivalent to 15+3x
A) 3(5+x)
B) 5(3+x)
C) 3(5+3x)
D) 5(3+3x)

Answers

Answer:

3(5+x)

Step-by-step explanation:

15+3x

5*3 + 3*x

Factor out 3

3(5+x)

15x+3=3 (5x+1) I have taken this question before

solve for x algebra help

Answers

Answer:

x=24

Step-by-step explanation:

Hi there!

We are given the following proportion:

[tex]\frac{2}{10}=\frac{3}{x-9}[/tex]

And we want to solve for x.

First, let's reduce [tex]\frac{2}{10}[/tex], as reducing fractions typically makes the process easier

[tex]\frac{2}{10}[/tex] is the same as [tex]\frac{1}{5}[/tex]

So:

[tex]\frac{1}{5}=\frac{3}{x-9}[/tex]

We can't do anything to [tex]\frac{3}{x-9}[/tex], but that's okay.

Now we can cross multiply, as this is a proportion

Multiply x-9 by 1 and 3 by 5

1(x-9)=3(5)

Multiply

x-9=15

Now this is an equation

Our goal is to isolate x on one side

So let's add 9 to both sides to remove it from the left side

x-9=15

 +9 +9

_________

x=24

Hope this helps!

Answer:

24

Step-by-step explanation:

Cross multiply:

2(x - 9) = 2x - 18

3(10) = 30

2x-18 = 30

   +18   +18

-----------------

  2x = 48

 -----   -----

   2       2

     x = 24

Hope this helped.

Which decimal is equivalent to 48 over 100

a. 0.048
b. 0.48
c. 4.08
d. 4.8​

Answers

Answer:

0.48

Step-by-step explanation:

hope it can work for you mark me as a brain liest

Find the length of x
. Assume the triangles are similar.

Answers

Answer:

x=2.24

Step-by-step explanation:

To do this problem, you must find the scale factor. Using two corresponding sides you can find it.

Using 2.4 and 3:

2.4 / 3 = 0.8

Scale factor: 0.8

Now find x:

2.8 × 0.8 = 2.24

x = 2.24

Hope this helped.

Which set of whole numbers but not natural numbers

Answers

Answer:

C

Step-by-step explanation:

C is the set with whole numbers as it contains 0 and natural numbers

jack o connel had $51,072 he wanted to share the money equally between 96 employees how much mone did each employee receive?

Answers

Answer:

$532

Step-by-step explanation:

We do 51,072 / 96 which is 532.

Each employee received $532.

The equation y=2(x-1)^2-5y=2(x−1)
2
−5y, equals, 2, left parenthesis, x, minus, 1, right parenthesis, squared, minus, 5 is graphed in the xyxyx, y-plane. Which of the following statements about the graph is true?

Answers

Answer:

(b) It is symmetrical about [tex]x = 1[/tex]

Step-by-step explanation:

Given

[tex]y = 2(x - 1)^2 - 5[/tex]

See attachment for options

Required

True statement about the graph

First, we check the line of symmetric

[tex]y = 2(x - 1)^2 - 5[/tex]

Expand

[tex]y = 2(x^2 - 2x + 1) - 5[/tex]

Open bracket

[tex]y = 2x^2 - 4x + 2 - 5[/tex]

[tex]y = 2x^2 - 4x -3[/tex]

A quadratic equation [tex]y = ax^2 + bx + c[/tex] has the following line of symmetry

[tex]x = -\frac{b}{2a}[/tex]

By comparison, the equation becomes:

[tex]x = -\frac{-4}{2*2}[/tex]

[tex]x = \frac{4}{4}[/tex]

[tex]x = 1[/tex]

Hence, the line of symmetry is at: [tex]x = 1[/tex]

(b) is true.

Answer: It is symmetrical about x=1

Step-by-step explanation:

A pair of shoes is on sale for 30% off. The original price is p. Which expression can be used to find the price of the shoes after the discount?


a) 0.30p


b) 0.70p


c) 1.30p


d) 30p

Answers

Answer:

Step-by-step explanation:

the answer is b

Find a (Round to the nearest tenth). PLS HURRY!!

Answers

Answer:

a = 56.3°

Step-by-step explanation:

tan(a) = 9/6 = 1.5

atan(1.5) = 56.31°

Answer:

[tex]\boxed {\boxed {\sf 56.3 \textdegree}}[/tex]

Step-by-step explanation:

We are asked to find the measure of angle a.

This triangle is a right triangle because of the small triangle in the corner representing a 90 degree or right angle. Therefore, we can use trigonometric functions. The three main functions are:

sinθ=opposite/hypotenuse cosθ= adjacent/hypotenuse tanθ= opposite/adjacent

The side measuring 6 is adjacent or next to angle a. The side measuring 9 is opposite angle a. Therefore, we will use the tangent function.

[tex]tan \theta= \frac{ opposite}{adjacent}[/tex]

[tex]tan \ a = \frac{ 9}{6}[/tex]

Since we are solving for an angle measure, we use the inverse trigonometric function.

[tex]tan ^{-1} * tan \ a = tan ^{-1} * \frac{9}6}[/tex]

[tex]a= tan ^{-1} * \frac{9}6}[/tex]

[tex]a= 56.30993247[/tex]

Round to the nearest tenth. The 0 in the hundredth place tells us to leave the 3 in the tenth place.

[tex]a \approx 56.3[/tex]

The measure of angle a is approximately 56.3 degrees.

The average of four different positive integers is 9. What is the greatest value for one of the integers?

Answers

Answer:

30

Step-by-step explanation:

Sum of those 4 integers is:

4*9 = 36

If the smallest ones are 1, 2 and 3, then the greatest possible integer is:

36 - (1 + 2 + 3) = 30
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